Conventionally, as a control system for a purpose of reducing a pumping loss of an internal combustion engine, there is a control system disclosed in Japanese Patent Application Laid-Open Publication No. 2001-164970, for example.
The control system disclosed in the Publication '970 has a detector that detects whether a fuel supply is stopped while a vehicle is travelling, and a detector that detects a catalyst temperature of an exhaust system.
An intake air amount of the internal combustion engine is increased when the fuel supply is stopped and the catalyst temperature is higher than a predetermined value.
The pumping loss is reduced by performing this control, and it is possible to increase an electrical power generation amount during regeneration of a generator connected with the internal combustion engine.
In the control system disclosed in the Publication '970, the control for reducing the pumping loss is performed when the catalyst temperature is higher than the predetermined value, and the control for reducing the pumping loss is not performed when the catalyst temperature is lower than the predetermined value.
Thus, although the catalyst temperature can be suppressed from dropping, an effect of reducing the pumping loss is limited.